A new SCons release, 4.8.0, is now available on the SCons download page:

    https://scons.org/pages/download.html


Here is a summary of the changes since 4.7.0:

NEW FUNCTIONALITY
-----------------

- GetSConsVersion() added to retrieve the SCons version.

DEPRECATED FUNCTIONALITY
------------------------

- Mark Python 3.6 support as deprecated. Use --warn=no-python-version
  to quiet the warning.

CHANGED/ENHANCED EXISTING FUNCTIONALITY
---------------------------------------

- Dump() with json format selected now recognizes additional compound types
  (UserDict and UserList), which improves the detail of the display.
  json output is also sorted, to match the default display.
- Python 3.13 changes the behavior of isabs() on Windows. Adjust SCons
  usage of this in NodeInfo classes to avoid test problems.
- Drop duplicated __getstate__ and __setstate__ methods in AliasNodeInfo,
  FileNodeInfo and ValueNodeInfo classes, as they are identical to the
  ones in parent NodeInfoBase and can just be inherited.
- All exceptions during the execution of an Action are now returned by value
  rather than by raising an exception, for more consistent behavior.
  NOTE: With this change, user created Actions should now catch and handle
  expected exceptions (whereas previously many of these were silently caught
  and suppressed by the SCons Action exection code).
- ParseFlags now sorts a --stdlib=libname argument into CXXFLAGS instead
  of CCFLAGS; the latter variable could cause a compiler warning.
- The implementation of Variables was slightly refactored, there should
  not be user-visible changes.
- MSVC: For msvc version specifications without an 'Exp' suffix, an express
  installation is used when no other edition is detected for the msvc version.
  This was the behavior for Visual Studio 2008 (9.0) through Visual Studio 2015
  (14.0).  This behavior was extended to Visual Studio 2017 (14.1) and Visual
  Studio 2008 (8.0).  An express installation of the IDE binary is used when no
  other IDE edition is detected.
- The vswhere executable locations for the WinGet and Scoop package managers were
  added to the default vswhere executable search list after the Chocolatey
  installation location.
- SCons.Environment.is_valid_construction_var() now returns a boolean to
  match the convention that functions beginning with "is" have yes/no
  answers (previously returned either None or an re.match object).
  Now matches the annotation and docstring (which were prematurely
  updated in 4.6). All SCons usage except unit test was already fully
  consistent with a bool.
- The Variables object Add method now accepts a subst keyword argument
  (defaults to True) which can be set to inhibit substitution prior to
  calling the variable's converter and validator.
- AddOption and the internal add_local_option which AddOption calls now
  recognize a "settable" keyword argument to indicate a project-added
  option can also be modified using SetOption.
  NOTE: If you were using ninja and using SetOption() for ninja options
  in your SConscripts prior to loading the ninja tool, you will now
  see an error. The fix is to move the SetOption() to after you've loaded
  the ninja tool.
- ListVariable now has a separate validator, with the functionality
  that was previously part of the converter. The main effect is to
  allow a developer to supply a custom validator, which previously
  could be inhibited by the converter failing before the validator
  is reached.
- When debugging (--debug=pdb), the filename SCsub is now recognized when
  manipulating breakpoints.

FIXES
-----

- OSErrors are now no longer hidden during the execution of Actions.
- Improved the conversion of a "foreign" exception from an action
  into BuildError by making sure our defaults get applied even in
  corner cases. Fixes Issue #4530
- MSVC: Visual Studio 2010 (10.0) could be inadvertently detected due to an
  sdk-only install of Windows SDK 7.1.  An sdk-only install of Visual Studio
  2010 is ignored as the msvc batch files will fail. The installed files are
  intended to be used in conjunction with the SDK batch file.  Similar protection
  was added for Visual Studio 2008 (9.0).
- MSVC: For Visual Studio 2005 (8.0) to Visual Studio 2015 (14.0), detection of
  installed files was expanded to include the primary msvc batch file, dependent
  msvc batch file, and compiler executable. In certain installations, the
  dependent msvc batch file may not exist while the compiler executable does exist
  resulting in a build failure.
- MSVC: Visual Studio 2008 (9.0) Visual C++ For Python was not detected when
  installed using the ALLUSERS command-line option:
      msiexec /i VCForPython27.msi ALLUSERS=1
  When installed for all users, Visual Studio 2008 (9.0) Visual C++ For Python is
  now correctly detected.
- MSVC: For Visual Studio 2008 (9.0), a full development edition (e.g., Professional)
  is now selected before a Visual C++ For Python edition. Prior to this change,
  Visual C++ For Python was selected before a full development edition when both
  editions are installed.
- The vswhere executable is frozen upon initial detection.  Specifying a different
  vswhere executable via the construction variable VSWHERE after the initial
  detection now results in an exception.  Multiple bugs in the implementation of
  specifying a vswhere executable via the construction variable VSWHERE have been
  fixed.  Previously, when a user specified vswhere executable detects new msvc
  installations after the initial detection, the internal msvc installation cache
  and the default msvc version based on the initial detection are no longer valid.
  For example, when no vswhere executable is found for the initial detection
  and then later an environment is constructed with a user specified vswhere
  executable that detects new msvc installations.
- MSVC: Visual Studio 2022 v143 BuildTools now supports msvc toolset versions from
  14.30 to 14.4X.  Fixes Issue #4543.
- The Clone() method now respects the variables argument (fixes #3590)

IMPROVEMENTS
------------

- Make the testing framework a little more resilient: the temporary
  directory for tests now includes a component named "scons" which can
  be given to antivirus software to exclude.
- Performance tweak: the __setitem__ method of an Environment, used for
  setting construction variables, now uses the string method isidentifier
  to validate the name (updated from microbenchmark results).
- MSVC: Visual Studio 2015 Express (14.0Exp) does not support the sdk version
  argument. Visual Studio 2015 Express does not support the store argument for
  target architectures other than x86.  Script argument validation now takes into
  account these restrictions.
- MSVC: Visual Studio 2015 BuildTools (14.0) does not support the sdk version
  argument and does not support the store argument.  Script argument validation now
  takes into account these restrictions.
- MSVC: The registry detection of VS2015 (14.0), and earlier, is now cached at runtime
  and is only evaluated once for each msvc version.
- MSVC: The vswhere detection of VS2017 (14.1), and later, is now cached at runtime and
  is only evaluated once using a single vswhere invocation for all msvc versions.

PACKAGING
---------

- setup.cfg logic now handled via pyproject.toml; consequently, setup.cfg
  was removed.


DOCUMENTATION
-------------

- Updated Value Node docs.
- Update manpage for Tools, and for the TOOL variable.
- Update manpage and user guide for Variables usage.
- Restructured API Docs build so main package contents are listed
  before contents of package submodules.
- Updated manpage description of Command "builder" and function.
- Updated the notes about reproducible builds with SCons and the example.
- Regularized header (copyright, licens) at top of documentation files using SPDX.
- Updated introductory section of manual page.



DEVELOPMENT
-----------

- Documentation build now properly passes through skipping the PDF
  (and EPUB) builds of manpage and user guide; this can also be done
  manually if directly calling doc/man/SConstruct and doc/user/SConstruct
  by adding SKIP_PDF=1. This should help with distro packaging of SCons,
  which now does not need "fop" and other tools to be set up in order to
  build pdf versions which are then ignored.
- .gitattributes has been setup to mirror .editorconfig's eol settings.
  The repo-wide line-ending is now `lf`, with the exception of a few
  Windows-only files using `crlf` instead. Any files not already fitting
  this format have been explicitly converted.
- Repository linter/formatter changed from flake8/black to ruff, as the
  latter grants an insane speed boost without compromising functionality.
  Existing settings were migrated 1-to-1 where possible.
- The test runner now recognizes the unittest module's return code of 5,
  which means no tests were run. SCons/Script/MainTests.py currently
  has no tests, so this particular error code is expected - should not
  cause runtest to give up with an "unknown error code".
- is_valid_construction_var() (not part of the public API) moved from
  SCons.Environment to SCons.Util to avoid the chance of import loops. Variables
  and Environment both use the routine and Environment() uses a Variables()
  object so better to move to a safer location.

Thanks to the following contributors listed below for their contributions to this release.
==========================================================================================
.. code-block:: text

    git shortlog --no-merges -ns 4.7.0..HEAD
        70  Mats Wichmann
        35  Joseph Brill
        26  William Deegan
         7  Raymond Li
         7  Thaddeus Crews
